#include <stdio.h>
int main()
{
    int x;
    scanf("%d", &x);

    if(x < 0)
    {
        printf("输入有误\n");
        return -1;
    }
    double y = 0;
    switch(x/10)
    {
        case 10:
            y += (x-100)*0.01;//+ 40*0.015 + 20*0.03 + 20*0.05 + 10*0.075 + 10*0.1; 
            x = 100;
           // break;
        case 9:
        case 8:   
        case 7:
        case 6:
            y +=  (x-60)*0.015 ;//+ 20*0.03 + 20*0.05 + 10*0.075 + 10*0.1;
            x = 60;
            //break;
        case 5:
        case 4:
            y +=  (x-40)*0.03 ;//+ 20*0.05 + 10*0.075 + 10*0.1;
            x = 40;
            //break;
        case 3:
        case 2:
            y +=  (x-20)*0.05 ;//+ 10*0.075 + 10*0.1;
            x = 20;
            //break; 
        case 1:
            y +=  (x-10)*0.075;// + 10*0.1;
            x = 10;
            //break; 
        default:
            y +=  x*0.1;
    }
    printf("y = %f\n", y);
}